JP4447367B2 - Injection valve after-injection reduction device - Google Patents

Abstract

The valve needle (1), of a fuel injection valve for an internal combustion motor and especially with spontaneous ignition, has a damping collar (4) and a chamber (5) filled with a damping fluid in the valve housing (2). At the end of the valve closing action, the collar penetrates into the damping fluid. The damping fluid is the motor fuel, with a free flow cross section (7) between the needle and the housing to allow a leakage flow to the damping chamber.

Description

  The present invention relates to a device for reducing post-injection of an injection valve with a valve needle guided in a housing.

  Since the valve needle of the injection valve closes at high speed, it collides with the valve seat, and rebounding at that time causes post-injection of the injection valve. For this reason, after completion of the predetermined injection, an indefinite amount of fuel reaches the combustion chamber of the engine with a small injection pressure. This results in an adverse effect on the engine combustion process and operating performance.

  It is an object of the present invention to reduce or completely prevent valve needle rebound and subsequent post-injection after the normal injection process by simple means.

  This object is based on the invention in a device of the type mentioned at the outset, in which the valve needle is provided with a damping collar, a damping chamber to which damping liquid is supplied is provided in the housing, and the damping collar is closed on the valve needle. The problem is solved by entering the attenuation chamber near the end of the movement.

  The damping that occurs near the end of the closing movement of the valve needle reduces the speed of the valve needle just before it hits the valve seat, so that the risk of rebound is reduced or disappears completely. Only a slight change in the shape of the relevant parts of the device is required, and no additional moving parts are required, resulting in a very simple configuration.

  In an advantageous embodiment of the invention, the damping liquid is a fuel for a self-igniting reciprocating internal combustion engine. This eliminates the need for a special damping liquid.

  Between the valve needle and the housing, an inflow opening cross section for allowing the leaked fuel to flow into the damping chamber may be provided. As a result, the damping liquid can be supplied to the damping chamber very easily. The cross section of the inflow opening is obtained within a working frame originally applied to the outer surface of the valve needle and the inner surface of the housing.

  It is preferable that an outflow opening cross section for allowing the attenuation liquid to flow out is provided between the attenuation collar and the inner wall of the attenuation chamber. This cross section can likewise be formed in the machining frame of the valve needle and the housing.

  Other advantageous embodiments and further developments of the invention will be understood from the dependent claims and the following description of the examples.

  FIG. 1 is a sectional view showing an important part of an injection valve of a self-ignition reciprocating internal combustion engine.

  In FIG. 1, 1 is a valve needle, and 2 is a housing for guiding the valve needle 1. The housing 2 is placed in the outer housing 3.

  The valve needle 1 comprises a circular damping collar 4 that goes into the damping chamber 5. The attenuation chamber 5 is formed in the housing 2 by cutting. Above the damping chamber 5, there is a return chamber 6 in the outer housing 3 connected to a return pipe (not shown) to the fuel storage tank. The diameter of the chamber 6 is larger than the diameter of the damping chamber 5.

  The outer diameter of the valve needle 1 and the inner diameter of the housing 2 are dimensioned so that an inflow opening cross section 7 for allowing the leaked fuel as the damping liquid to flow into the damping chamber 5 is formed between them. Further, the outer diameter of the attenuation collar 4 and the inner diameter of the attenuation chamber 5 are mutually set such that when the attenuation collar 4 enters the attenuation chamber 5, an annular outflow opening cross section 8 is formed that allows the attenuation liquid to flow out of the attenuation chamber 5. Determine in harmony. The attenuation start point is determined by the attenuation collar 4 entering the attenuation chamber 5, and the attenuation strength is determined by the size of the cross section 8 of the outflow opening. At this time, the attenuation collar 4 is disposed on the valve needle 1 so that the volume of the attenuation chamber 5 is 2 to 4 times larger than the volume excluded when the attenuation collar 4 enters the attenuation chamber 5. Furthermore, the area of the outflow opening section 8 is, for example, 1.5 to 3 times the area of the inflow opening section 7. Here, for reasons of manufacturing, the inflow opening cross section 7 and the outflow opening cross section 8 are preferably formed in an annular shape. However, the opening cross section can also be formed by a groove-like depression of each part.

  During the closing movement of the valve needle 1 proceeding in the direction of the arrow a, the damping collar 4 enters the damping chamber 5 near the end of the movement. As a result, the damping liquid is pushed out from the damping chamber 5 through the outflow opening section 8. For this reason, the speed at which the valve needle 1 moves in the direction of arrow a decreases. Along with the deceleration near the end of the closing movement of the valve needle 1, the adverse effects of post-injection on the combustion process and operating performance of the engine and the life of the injection nozzle are reduced.

Sectional drawing of the principal part of the injection valve in a self-ignition reciprocating internal combustion engine.

Explanation of symbols

1 Valve needle, 2 housing, 4 damping collar, 5 damping chamber, 7 inflow opening cross section, 8 outflow opening cross section

Claims (3)

A post-injection reduction device for an injection valve with a valve needle guided in a housing,
The valve needle (1) is provided with a damping collar (4), a damping chamber (5) to which damping fluid is supplied is provided in the housing (2), and the damping collar (4) is at the end of the closing movement of the valve needle. In the device that enters the attenuation chamber (5) in the vicinity,
Between the valve needle (1) and the housing (2), an inflow opening cross section (7) for allowing leaked fuel to flow into the damping chamber (5) is provided,
Between the damping collar (4) and the inner wall of the damping chamber (5), there is an outflow opening cross section (8) for the damping liquid to flow out,
The damping collar (4) has a valve needle (4) so that the volume of the damping chamber (5) is 2 to 4 times the volume excluded by the damping collar (4) in the vicinity of the end of the closing movement of the valve needle (1). 1) and
The area of the outflow opening section (8) between the damping collar (4) and the damping chamber (5) is 1.5 times the area of the inflow opening section (7) between the valve needle (1) and the housing (2). A device for reducing the post-injection of the injection valve, characterized in that it is ~ 3 times .   2. The apparatus according to claim 1, wherein the damping liquid is a fuel for a self-ignition reciprocating internal combustion engine. 3. The device according to claim 1, wherein the inflow opening cross section (7) and the outflow opening cross section (8) are annular .

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